Supercontinuum laser-based absorptance measurement for materials in the solar spectral band

• An innovative method applying supercontinuum(SC) laser to integrating sphere reflectance measurements. • Spectrally continuous absorptance of 4th-generation Concentrated Solar Power(CSP) material SiC was originally measured. • Experimental SiC data were comparatively verified against NIST. To address the issues of low signal-to-noise ratio (SNR) in traditional absorptance measurements of solar materials, this study proposes a high-precision spectral absorptance measurement scheme based on a supercontinuum(SC) laser combined with integrating sphere reflectometry. By comparing source performance, analyzing calibration samples, and implementing aperture coefficient correction, stray light compensation, and laser drift correction, a measurement system covering the 500 nm–2200 nm spectral range was established. The SNR of the supercontinuum-laser-based system exceeds that of halogen-tungsten lamps by 2–3 orders of magnitude; At 50 % of maximum rated power, the laser-maintained signal stability (relative standard deviation, RSD) was ≤0.35 %; At room temperature, the measured absorptance of samples (Pyromark 2500 high-temperature paint and sandblasted aluminum plate) exhibited absolute deviations < 0.03 from the reference values calibrated by the National Institute of Metrology of China (NIM) across the 500 nm–2000 nm spectral range. The expanded uncertainty (k = 2) for SiC spectral absorptance measurements was determined as 3.5 %, consistent with the National Institute of Standards and Technology (NIST) reference data within experimental uncertainties. The experimental results demonstrate the measurement accuracy and operational reliability of the developed experimental system for absorptance characterization of solar energy materials.